/**
 * @param {number[]} runes
 * @return {number}
 */
var runeReserve = function (runes) {
  runes.sort((a, b) => a - b)
  let left = 0, right, res = 0
  for (right = 1; i < runes.length; i++) {
    if (runes[right] - runes[right-1] >1) {

      res = Math.max(res, right - left + 1)
      left++
    }
  }
  return res
};